1. Field of the Invention
The present invention relates to a numerical controller having a function for displaying physical data of a machine tool, such as a speed of a drive axis and a representative point of a tool, with reference to movement distance of the drive axis and the tool.
2. Description of the Related Art
In a machine tool, the same processing program may be carried out based on different processing conditions, such as processing speed. When it is necessary to adjust the machine tool in such a case, it is important to compare data after the adjustment to past data before the adjustment. Therefore, a waveform display device has been proposed, wherein sets of time-series data, such as speed of a drive axis or a tool tip point obtained from a numerical controller, are overlapped with each other and displayed. For example, Japanese Unexamined Patent Publication (Kokai) No. 2003-75472 discloses a technique for displaying two servo waveforms based on servo information from a controller, wherein the two waveforms are overlapped with each other within a single display frame.
Further, Japanese Unexamined Patent Publication (Kokai) No. 2004-216715 discloses a technique for displaying a three-dimensional graph of changed cycle patterns on a monitor device of an injection machine, wherein first, second and third axes represent time, a variable such as injection pressure, and a forming cycle, respectively.
When the processing speed is changed, processing time is also changed accordingly, even if the shape of a commanded trajectory is not changed. Therefore, in relation to a plurality of different processing conditions, when physical information such as the speed of the tool tip point is compared as time-series data, it is difficult to compare the data at the same processing position. For example, although Japanese Unexamined Patent Publication (Kokai) No. 2003-75472 discloses the overlapping of time axis-based data, it does not disclose the overlapping of movement distance-based data, which does not depend on the time axis. On the other hand, the invention of Japanese Unexamined Patent Publication (Kokai) No. 2004-216715 is intended to overlap the changed pattern of each cycle while representing the forming cycle on the third axis, however, the time-series data is compared while representing the time on the horizontal axis, and thus the data is not compared with reference to the movement distance.